coastal communities

Salt Marsh Communities

•Found in protected estuarine habitats

• Created by grasses, which stabilize soft sediment substrate

Salt Marshes – Physical Characteristics

•Intertidal habitats

• Lower elevations of salt marsh are usually submerged daily for several hours, while upper border of salt marsh is only submerged once or twice a month.

Salt Marsh-Zonation

• Few species can be good at everything. Salt marsh grasses are usually either good competitors or able to tolerate the physiologically stressful conditions of the low salt marsh.

• Grasses and flowering plants that are good stress tolerators like Spartina alterniflora dominate the low marsh.

Salt Marsh - Distribution

Worldwide

-low seacoasts

-inside barrier bars and beaches

-in estuaries

-on deltas

Salt Marshes Plants & Animals

• Important nursery grounds for many commercially important fishes

• Important feeding and breeding habitat for waterfowl

Plant roots hold the sediment in and are a place for animals to hide.

Uses • Natural filter system Natural barrier against coastal flooding

• Nursery ground for economically important species

• Beautiful!

Human Abuses

• Construction/Development (habitat loss)

• Ditching for mosquito “control”

• Overharvesting of resources

Dominant Animals

• Birds

• Fish

• Invertebrates– Crustaceans– Mollusks

Geukensia demissa

Agelaius phoeniceus

Limulus polyphemus

Salt Marsh Plants

• Halophytes - plants that tolerate salty water -Some push salt through pores

-Some push salt to the end of the plant and drop the end off - Salicornia

Spartina patens

Spartina alterniflora

Phragmites australis – that all too common, common reed

Salt Marsh at Low Tide

Salt Marsh at High Tide

To Learn More About Salt Marshes

Local salt marshes:

www.chipr.sunysb.edu/eserc/longis/flaxpond.html

Regional salt marshes:

http://www.edc.uri.edu/restoration/html/gallery/plants/reed.htm

http://serc.carleton.edu/introgeo/roleplaying/examples/tide.html

http://www.nationalgeographic.com/xpeditions/lessons/08/g35/oceans35.html

http://www.dnr.sc.gov/marine/pub/seascience/dynamic.html

Mud (Tidal) Flats

Mud (Tidal) Flats – Physical Characteristics

• Some areas of estuary wetlands are relatively devoid of plant matter. These Soft sediment habitats are the Tidal (Mud) Flats.

• They occur along outer edges of the salt marshes where low current flow allows fine sediment to drop out of suspension

Who lives in Mud (Tidal) Flats?• Home to a diverse

community of invertebrates:

Snails, Clams & Segmented worms-all move through the bottom, mixing deeper, oxygen-starved sediments with surface sediments (bioturbation).

Mud flats provide habitat/feeding ground for many invertebrates –

and their predators

Digging Clams

Human Uses

• Similar to salt marsh

- important nursery ground for young fish

- barrier from storm damage to land/coastal flooding

- beautiful

Threats to Mud (Tidal) Flats• Change in current

velocity• Development of

surrounding marshes• Dredging• Global warming

Seagrass Distribution-Shallow sub-tidal habitats created

by marine grasses-Found in estuaries and lagoons in

both temperate and tropical systems throughout the world

Values of Seagrasses

-Modify environment by reducing current velocity, which can in turn affect sedimentation rates & soil grain size

-Help slow down storms moving inland-Increase habitat complexity, reducing

predation intensity-FOOD, SHELTER, NURSERY !!

Values of Seagrasses continued

Increased number of individuals and species in seagrass

bed, compared to

bare or sandy areas outside the

bed.Our local seagrass is

Eelgrass

Who Lives There?Values of Seagrasses continued

-Fish, crabs, shrimp, and scallops are much more common inside sea grass beds than outside them. Some species, such as clams and scallops, also grow faster within a sea grass bed.

Threats To Seagrasses• Boat propeller damage

• Global warming, sea level rise

• Water quality & clarity decreases from runoff (making photosynthesis difficult)

• Brown Tide

To learn more about Seagrasses:http://www.sms.si.edu/IRLspec/Seagrass_Habitat.htm

http://www.ncl.ac.uk/tcmweb/tcm/sglinks.htm

Rocky Intertidal Communities

Physical Characteristics:Dependent on

tides-periodically covered by water

or exposed to elements

Rocky – cobble to boulder sized

sediment

Value of Rocky Intertidal

Structure, habitat for economically & environmentally important species

Threats to the Rocky Intertidal

• Global Climate Change & Sea Level Rise

• Waste disposal/sewage disposal

• Overcollecting, trampling by humans

http://www.youtube.com/watch?v=25F7xMVNt-w

Barnacles Feeding

Rocky Intertidal Flora & Fauna

Helpful Links to Communities

Salt Marsh & Rocky Shores:http://www.uri.edu/cels/bio/rishores/

home.htmBarnacles!

http://www.youtube.com/watch?v=M2ow4sB-RQs&feature=related